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sched: remove expired_starving()

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remove the expired_starving() heuristics from the core scheduler.

CFS does not need it, and this did not really work well in practice
anyway, due to the rq->nr_running multiplier to STARVATION_LIMIT.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Ingo Molnar 2007-07-09 18:51:59 +02:00
parent f2ac58ee61
commit c18a17329b
1 changed files with 1 additions and 22 deletions
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23
kernel/sched.c
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@ -3240,27 +3240,6 @@ unsigned long long task_sched_runtime(struct task_struct *p)
return ns; return ns;
} }
/*
* We place interactive tasks back into the active array, if possible.
*
* To guarantee that this does not starve expired tasks we ignore the
* interactivity of a task if the first expired task had to wait more
* than a 'reasonable' amount of time. This deadline timeout is
* load-dependent, as the frequency of array switched decreases with
* increasing number of running tasks. We also ignore the interactivity
* if a better static_prio task has expired:
*/
static inline int expired_starving(struct rq *rq)
{
if (rq->curr->static_prio > rq->best_expired_prio)
return 1;
if (!STARVATION_LIMIT || !rq->expired_timestamp)
return 0;
if (jiffies - rq->expired_timestamp > STARVATION_LIMIT * rq->nr_running)
return 1;
return 0;
}
/* /*
* Account user cpu time to a process. * Account user cpu time to a process.
* @p: the process that the cpu time gets accounted to * @p: the process that the cpu time gets accounted to
@ -3373,7 +3352,7 @@ static void task_running_tick(struct rq *rq, struct task_struct *p)
if (!rq->expired_timestamp) if (!rq->expired_timestamp)
rq->expired_timestamp = jiffies; rq->expired_timestamp = jiffies;
if (!TASK_INTERACTIVE(p) || expired_starving(rq)) { if (!TASK_INTERACTIVE(p)) {
enqueue_task(p, rq->expired); enqueue_task(p, rq->expired);
if (p->static_prio < rq->best_expired_prio) if (p->static_prio < rq->best_expired_prio)
rq->best_expired_prio = p->static_prio; rq->best_expired_prio = p->static_prio;